1. Field of Invention
This invention relates to producing visual effects, and in a specific embodiment to devices placed or worn in relation to the eye to provide novel visual effects for various applications.
2. State of the Prior Art
When a semi-transparent film is placed in front of the eyes of a person, a scene as viewed by the person will be modified. In particular, holographic gratings have been placed in spectacle frames to produce a spreading of light of different colors. When these spectacles are worn by the person, the objects in a natural scene appear to be smeared along a line. When white light sources are present, the spectacles cause the light to spread in a multicolor streak along a single direction. In some products, the spectacles contains two such gratings for each eye arranged perpendicular to each other, thus causing the appearance of two streaks in perpendicular directions. These color-spreading spectacles are sold under a variety of trade names. The color-spreading spectacles are, however, unable to superimpose arbitrary, pre-selected patterns, such as letters of the alphabet or simple line drawings, on the scene. Furthermore, the gratings produce color separated smears of every object in the scene.